The favourites delivered in emphatic style in the Rio de Janeiro pool Sunday as Sweden's Sarah Sjostrom, Britain's Adam Peaty and American Katie Ledecky produced world record performances to win gold and veteran Michael Phelps claimed his 19th Olympic title.
Sjostrom started the records tumbling in the women's 100-metre butterfly by touching up in 55.48 seconds, 0.16 under her own previous record.
Peaty was next, carving 0.42 seconds off the men's 100-metre breaststroke mark he set in heats Saturday, to post 57.13 in the final.
The 19-year-old Ledecky then produced the most dominant performance of the three to win in 3:56.46 minutes, lowering her own 2014 record by a massive 1.91 seconds.
Her compatriot Phelps then capped a thrilling session in the pool as part of the US team, alongside Caeleb Dressel, Ryan Held and Nathan Adrian, for his 23rd medal overall.
Sjostrom took her gold from 16-year-old Penny Oleksiak of Canada, who swum a junior world record of 56.46. American Dana Vollmer, champion at London 2012, had to settle for bronze.
The gold is Sjostrom's first Olympic medal to go with four world championship titles.
“It’s hard to believe I have won an Olympic medal,” Sjostrom said straight after her swim. “I’ve had lots of ups and downs. I’m so happy.”
Peaty, 21, also took his first Olympic medal have comprehensively dethroned South Africa's 2012 champion Cameron Van der Burgh who was a distant second in 58.69 while American Cody Miller took bronze in a national record of 58.87.
"It's surreal. After my race I needed to slap something and there was just the water right there," Peaty said of his wild celebration. "It was crazy. It's amazing and I probably won't be able to sleep tonight.
"[It means] Absolutely everything. All the years of hardship. I've come back time after time and every time someone has got me down, I've come back stronger."
Ledecky won 800m gold in London 2012 and over the last four years has developed into by far by the best women's distance freestyler in the word. She had clear water to her rivals after just 150 metres and the only issues would be how much she could take off the world record and who would claim the minor medals.
"[The time of] 3:56 was the goal I set after [the] Barcelona 2013 [world championships]," Ledecky said. "So it feels really good. I'm pumped. I felt good throughout."
Carlin, who swam a personal best to still finish nearly five seconds behind, did enough to edge another American, Leah Smith, into bronze.
It is Ledecky's first gold of the Games after a relay silver Saturday and she has a strong chance of retaining the 800m and adding the 200m to her list of honours.
Phelps on the other hand is no stranger to Olympic gold, and the veteran at his fifth Games played a crucial role in pulling his team clear in the second leg after the pack stayed with Dressel.
Held and Adrian had little trouble in holding off their rivals with France finishing second and Australia third. The Russians, booed on arrival, took fourth with hosts Brazil fifth.
"On the block I thought my heart was going to explode, I was so hyped, so excited," Phelps said.
Held was seen in tears immediately afterwards and admitted "he couldn't hold back the emotions," upon victory, something that the 31-year-old Phelps was happy to encourage - even if he is presently unlikely to target Tokyo 2020.
"These guys are awesome," he said. "They will be there in four years. You got this. I'm out."
In semi-finals, China's Sun Yang, the centre of a tit-for-tat row over doping with Australia's Mack Horton following their 400m freestyle duel on Saturday, topped the 200m free. The main contenders all survived but British world champion James Guy took the eighth and final spot by just 1 hundredth of a second.
The controversial Russian Yulia Efimova, twice banned for doping, who only secured her Rio participation by winning a Court of Arbitration for Sport case last week, was booed - apparently from the athletes' block in the stadium - as she qualified second for the women's 100m breaststroke final.
American David Plummer was quickest in the men's 100m backstroke while compatriot Kathleen Baker was fastest in the women's equivalent.